Doppler adaptation using pilot patterns within single user, multiple user, multiple access, and/or MIMO wireless communications

• US 20120269142A1
• Filed: 04/23/2012
• Published: 10/25/2012
• Est. Priority Date: 04/24/2011
• Status: Abandoned Application

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Porat, Ron, Erceg, Vinko
• Application Number:
  US13/453,998
• Publication Number:
  US 20120269142A1
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2603 Signal structure ensuring backward compatibility with legacy system
• CPC Class Codes: H04L 27/26035 Maintenance of orthogonality, e.g. for signals exchanged between cells or users, or by using covering codes or sequences using different training sequence per antenna H04B7/0684; code allocation H04J13/16
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2618 Reduction thereof using auxiliary subcarriers
• CPC Class Codes: H04L 27/2666 Acquisition of further OFDM parameters, e.g. bandwidth, subcarrier spacing, or guard interval length
• CPC Class Codes: H04W 52/18 TPC being performed according to specific parameters
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Doppler adaptation using pilot patterns within single user, multiple user, multiple access, and/or MIMO wireless communications. Within a communication system employing orthogonal frequency division multiplexing (OFDM) signaling, pilots may be adaptively and/or selectively located at different respective sub-carrier or tone locations within different respective symbols based on one or more patterns. In some implementations, decimation may also be performed such that not necessarily all respective tone or sub-carrier locations are covered within one particular group. Multiple respective groups may be employed to cover all possible tone or sub-carrier locations with at least one pilot over a particular number of symbols. In a receiver communication device operating using such decimation, interpolation over the decimated set of tones or sub-carriers may be made to effectuate channel estimate updates.

Claims

1. An apparatus, comprising:

a baseband processing module selectively to generate at least one packet having a plurality of symbols, wherein at least a subset of the plurality of symbols, corresponding to at least one long training field (LTF) preceded by a short training field (STF) among a plurality of data fields within the at least one packet, having a plurality of pilots at different respective subcarrier or tone locations therein based on at least one pattern; and

at least one antenna to transmit a signal corresponding to the at least one packet to at least one additional apparatus; and

wherein;

a first symbol of the at least a subset of the plurality of symbols including a first pilot at a first subcarrier or tone location therein and a second pilot at a second subcarrier or tone location therein; and

a second symbol of the at least a subset of the plurality of symbols including the first pilot at a third subcarrier or tone location therein and the second pilot at a fourth subcarrier or tone location therein; and

the apparatus to employ the STF for at least one of automatic gain control (AGC) and AGC estimation.

2. The apparatus of claim 1, wherein:

the second plurality of subcarrier or tone locations each respectively being offset from the first plurality of subcarrier or tone locations.

3. The apparatus of claim 1, wherein:

at least one of the first plurality of subcarrier or tone locations and the second plurality of subcarrier or tone locations being uniformly distributed among an available plurality of subcarrier or tone locations within at least one orthogonal frequency division multiplexing (OFDM) symbol of the signal.

4. The apparatus of claim 1, wherein:

the at least one additional apparatus to receive the signal including the plurality of symbols from the apparatus;

based on a first at least one symbol of the at least a subset of the plurality of symbols within the signal, the at least one additional apparatus to make a first channel estimate of a communication channel between the apparatus and the at least one additional apparatus; and

based on a second at least one symbol of the at least a subset of the plurality of symbols within the signal, the at least one additional apparatus to make a second channel estimate of the communication channel between the apparatus and the at least one additional apparatus.

5. The apparatus of claim 1, wherein:

the apparatus is an access point (AP); and

the at least one additional apparatus is a wireless station (STA).

6. An apparatus, comprising:

a baseband processing module selectively to generate at least one packet having a plurality of symbols, wherein at least a subset of the plurality of symbols having a plurality of pilots at different respective subcarrier or tone locations therein based on at least one pattern; and

at least one antenna to transmit a signal corresponding to the at least one packet to at least one additional apparatus.

7. The apparatus of claim 6, wherein:

the at least a subset of the plurality of symbols corresponding to at least one long training field (LTF) preceded by a short training field (STF) among a plurality of data fields within the at least one packet; and

the apparatus to employ the STF for at least one of automatic gain control (AGC) and AGC estimation.

8. The apparatus of claim 6, wherein, based on the at least one pattern:

a first symbol of the at least a subset of the plurality of symbols including a first plurality of pilots at a first plurality of subcarrier or tone locations therein; and

a second symbol of the at least a subset of the plurality of symbols including a second plurality of pilots at a second plurality of subcarrier or tone locations therein each respectively being offset from the first plurality of subcarrier or tone locations.

9. The apparatus of claim 6, wherein, based on the at least one pattern:

at least one symbol of the at least a subset of the plurality of symbols including a plurality of pilots at a plurality of subcarrier or tone locations therein; and

the plurality of subcarrier or tone locations being uniformly distributed among an available plurality of subcarrier or tone locations within at least one orthogonal frequency division multiplexing (OFDM) symbol of the signal.

10. The apparatus of claim 6, wherein, based on the at least one pattern:

a first symbol of the at least a subset of the plurality of symbols including a first pilot at a first subcarrier or tone location therein and a second pilot at a second subcarrier or tone location therein; and

a second symbol of the at least a subset of the plurality of symbols including the first pilot at a third subcarrier or tone location therein and the second pilot at a fourth subcarrier or tone location therein.

11. The apparatus of claim 6, wherein, based on the at least one pattern:

a first symbol of the at least a subset of the plurality of symbols including a first pilot at a first subcarrier or tone location therein and a second pilot at a second subcarrier or tone location therein; and

a second symbol of the at least a subset of the plurality of symbols including the first pilot at the first subcarrier or tone location therein and the second pilot at a third subcarrier or tone location therein.

12. The apparatus of claim 6, wherein:

the at least one additional apparatus to receive the signal including the plurality of symbols from the apparatus;

based on a first at least one symbol of the at least a subset of the plurality of symbols within the signal, the at least one additional apparatus to make a first channel estimate of a communication channel between the apparatus and the at least one additional apparatus; and

based on a second at least one symbol of the at least a subset of the plurality of symbols within the signal, the at least one additional apparatus to make a second channel estimate of the communication channel between the apparatus and the at least one additional apparatus.

13. The apparatus of claim 6, wherein:

the apparatus is an access point (AP); and

the at least one additional apparatus is a wireless station (STA).

14. A method for operating a communication device, the method comprising:

selectively generating at least one packet having a plurality of symbols, wherein at least a subset of the plurality of symbols having a plurality of pilots at different respective subcarrier or tone locations therein based on at least one pattern; and

via at least one antenna of the communication device, transmitting a signal corresponding to the at least one packet to at least one additional communication device.

15. The method of claim 14, wherein:

the at least a subset of the plurality of symbols corresponding to at least one long training field (LTF) preceded by a short training field (STF) among a plurality of data fields within the at least one packet; and

further comprising;

employing the STF for at least one of automatic gain control (AGC) and AGC estimation.

16. The method of claim 14, wherein:

a first symbol of the at least a subset of the plurality of symbols including a first plurality of pilots at a first plurality of subcarrier or tone locations therein; and

a second symbol of the at least a subset of the plurality of symbols including a second plurality of pilots at a second plurality of subcarrier or tone locations therein each respectively being offset from the first plurality of subcarrier or tone locations.

17. The method of claim 14, wherein:

at least one symbol of the at least a subset of the plurality of symbols including a plurality of pilots at a plurality of subcarrier or tone locations therein; and

the plurality of subcarrier or tone locations being uniformly distributed among an available plurality of subcarrier or tone locations within at least one orthogonal frequency division multiplexing (OFDM) symbol of the signal.

18. The method of claim 14, wherein:

a first symbol of the at least a subset of the plurality of symbols including a first pilot at a first subcarrier or tone location therein and a second pilot at a second subcarrier or tone location therein; and

a second symbol of the at least a subset of the plurality of symbols including the first pilot at a third subcarrier or tone location therein and the second pilot at a fourth subcarrier or tone location therein.

19. The method of claim 14, wherein:

the at least one additional communication device receiving the signal including the plurality of symbols from the communication device;

based on a first at least one symbol of the at least a subset of the plurality of symbols within the signal, the at least one additional communication device making a first channel estimate of a communication channel between the communication device and the at least one additional communication device; and

based on a second at least one symbol of the at least a subset of the plurality of symbols within the signal, the at least one additional communication device making a second channel estimate of the communication channel between the communication device and the at least one additional communication device.

20. The method of claim 14, wherein:

the communication device is an access point (AP); and

the at least one additional communication device is a wireless station (STA).